Enhancing the bifunctional oxygen reduction and evolution activity of CoNC by introducing a trace amount of Fe.

The potential application of zinc air batteries to tackle the energy shortage and environmental crisis has proposed new requirements of bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Utilizing the special spatial structure of zeolitic imidazolate framework-67 (ZIF-67) as an ideal research platform, the effect of a trace amount of Fe on the composition and structure of as-obtained Fe-CoNC catalysts was investigated. It was revealed that, due to the increased exposed pore structure and metal species located at the near surface, the active sites for the ORR/OER on Fe-CoNC are highly exposed, greatly boosting the activity to the reduction and evolution of oxygen in alkaline media. ZABs with Fe-CoNC have the highest maximum power density of 200 mW cm-2 when operated at current densities as high as 328 mA cm-2, better than not only Fe-free CoNC, but also precious metal-based references with the same catalyst loading.

Combined prognostic significance of white blood cell count and D-dimer on in-hospital outcomes of acute ischemic stroke.

BACKGROUND AND AIMS: The prognostic significance of combination of white blood cell (WBC) and D-dimer on acute ischemic stroke (AIS) remains to be explored. We aimed to investigate the combined effect of WBC and D-dimer levels on in-hospital outcomes of AIS patients. METHODS AND RESULTS: 801 AIS patients were included. Patients were divided into four groups according to the cut-point identified by receiver operating characteristic (ROC) curve of D-dimer (1.105 µg/L) and WBC (7.05 × 109/L): LWLD (low WBC count and low D-dimer), LWHD (low WBC count and high D-dimer), HWLD (high WBC count and low D-dimer), and HWHD (high WBC count and high D-dimer). HWHD group had the highest cumulative incidence of in-hospital mortality (hazard ratio, 5.79; 95%CI, 1.71-19.58, P = 0.006). Patients in HWHD group were 4.14 fold more likely to have in-hospital pneumonia (odds ratio, 4.14; 95%CI, 2.09-8.21; P < 0.001), compared with those in LWLD group. The area under curve (AUC) of the combination of WBC and D-dimer levels for in-hospital mortality and pneumonia was larger than that of WBC and D-dimer alone (0.920 vs. 0.900 vs. 0.915; 0.831 vs. 0.829 vs. 0.807). CONCLUSIONS: The combination of WBC count and D-dimer levels at admission was independently associated with in-hospital outcomes of AIS patients. The addition of WBC to D-dimer levels had a tendency to improve the predictive power for in-hospital mortality and pneumonia.

A Cycle Slip Detection and Repair Method Based on Inertial Aiding for BDS Triple-Frequency Signals.

Cycle slip detection and repair is a prerequisite to obtain high-precision positioning based on a carrier phase. Traditional triple-frequency pseudorange and phase combination algorithm are highly sensitive to the pseudorange observation accuracy. To solve the problem, a cycle slip detection and repair algorithm based on inertial aiding for a BeiDou navigation satellite system (BDS) triple-frequency signal is proposed. To enhance the robustness, the INS-aided cycle slip detection model with double-differenced observations is derived. Then, the geometry-free phase combination is united to detect the insensitive cycle slip, and the optimal coefficient combination is selected. Furthermore, the L2-norm minimum principle is used to search and confirm the cycle slip repair value. To correct the INS error accumulated over time, the extended Kalman filter based on the BDS/INS tightly coupled system is established. The vehicular experiment is conducted to evaluate the performance of the proposed algorithm from a few aspects. The results indicate that the proposed algorithm can reliably detect and repair all cycle slips that occur in one cycle, including the small and insensitive cycle slips as well as the intensive and continuous cycle slips. Additionally, in signal-challenged environments, the cycle slips occurring 14 s after a satellite signal outage can be correctly detected and repaired.

Road-Network-Map-Assisted Vehicle Positioning Based on Pose Graph Optimization.

Satellite signals are easily lost in urban areas, which causes difficulty in vehicles being located with high precision. Visual odometry has been increasingly applied in navigation systems to solve this problem. However, visual odometry relies on dead-reckoning technology, where a slight positioning error can accumulate over time, resulting in a catastrophic positioning error. Thus, this paper proposes a road-network-map-assisted vehicle positioning method based on the theory of pose graph optimization. This method takes the dead-reckoning result of visual odometry as the input and introduces constraints from the point-line form road network map to suppress the accumulated error and improve vehicle positioning accuracy. We design an optimization and prediction model, and the original trajectory of visual odometry is optimized to obtain the corrected trajectory by introducing constraints from map correction points. The vehicle positioning result at the next moment is predicted based on the latest output of the visual odometry and corrected trajectory. The experiments carried out on the KITTI and campus datasets demonstrate the superiority of the proposed method, which can provide stable and accurate vehicle position estimation in real-time, and has higher positioning accuracy than similar map-assisted methods.

Does prolonged emergency department length of stay(EDLOS) affect the outcomes of acute ischemic stroke patients?

BACKGROUND AND PURPOSE: The effect of emergency department length of stay (EDLOS) on outcomes of patients with acute ischemic stroke (AIS) remains largely unexamined. We aimed to investigate the association between EDLOS and outcomes in AIS patients. METHODS: 618 AIS patients were enrolled. Baseline demographics, vascular risk factors, ED admission information, hyperacute treatment of AIS and stroke severity were collected. Stroke progression was defined as any new neurological symptoms/signs or any neurological worsening within 7 days after stroke onset and poor prognosis was defined as modified Rankin Scale(mRS) scores>2 at 30 day. The effect of EDLOS on stroke progression and prognosis was assessed. RESULTS: The median EDLOS was 2.5 h (1.4-6.9 h). On multivariable linear regression, presentation month between Apr. and Jun., admission at the ED between 7 am to 3 pm(P = 0.036), transferring to stroke unit, receiving endovascular interventional treatment, onset on holidays, and progressive stroke were associated with shorter EDLOS(all P < 0.05). A shorter EDLOS was significantly associated with an increased risk of stroke progression (P = 0.007). Patients with the lowest EDLOS (≤1.35 h) were 2-3 fold more likely to have stroke progression, compared with those with the highest EDLOS (>6.93 h) (OR, 2.52; 95% CI, 1.29-4.93; P = 0.043). However, no significant association between EDLOS and stroke prognosis was revealed. CONCLUSIONS: In AIS patients, shorter EDLOS was associated with the increased risk of stroke progression, possibly reflecting prioritized admission of more severely affected patients at high risk of stroke progression. EDLOS alone might be an insufficient indicator of stroke care in the ED.

Monocular Visual Position and Attitude Estimation Method of a Drogue Based on Coaxial Constraints.

In aerial refueling, there exists deformation of the circular feature on the drogue's stabilizing umbrella to a certain extent, which causes the problem of duality of position estimation by a single circular feature. In this paper, a monocular visual position and attitude estimation method of a drogue is proposed based on the coaxial constraints. Firstly, a procedure for scene recovery from one single circle is introduced. The coaxial constraints of the drogue are proposed and proved to be useful for the duality's elimination by analyzing the matrix of the spatial structure. Furthermore, we came up with our method, which is composed of fitting the parameters of the spatial circles by restoring the 3D points on it, using the two-level coaxial constraints to eliminate the duality, and optimizing the normal vector of the plane where the inner circle is located. Finally, the effectiveness and robustness of the method proposed in this paper are verified, and the influence of the coaxial circle's spatial structure on the method is explored through simulations of and experiments on a drogue model. Under the interference of a large amount of noise, the duality elimination success rate of our method can also be maintained at a level that is more than 10% higher than others. In addition, the accuracy of the normal vector obtained by the fusion algorithm is improved, and the mean angle error is reduced by more than 26.7%.

Preparation and antioxidant properties of crayfish (Procambarus clarkii) By-products protein hydrolysates and ultra filtration fractions.

Protein isolate from crayfish by-products (CBPI) were hydrolyzed using Alcalase, neutrase, pancreatin and bromelain. Hydrolysis by Alcalase had more remarkable digesting efficiency on crayfish by-products protein than that by the other enzymes. Therefore, protein hydrolysate from Alcalase digestion (CBPHa) was selected to be fractionated by ultrafiltration according to molecular weight into three fractions F1 (MW <1kDa), F2 (MW 1-3kDa) and F3 (MW 3-10kDa). The amino acid determination revealed that CBPI had essential amino acid (EAA) close to that required for human protein synthesis. In vitro activity experiments showed that CBPHa and its fractions possessed considerable antioxidant activity. F1 exhibited the highest DPPH, superoxide radicals scavenging activities and Fe2+ chelating ability, whereas F2 showed the best hydroxyl radicals scavenging capacity and reducing power. In addition, all the fractions showed higher super oxide radical scavenging activity than the crude hydrolysates. Our findings suggest that CBPHa and their ultra filtration fractions have the potential for use in nutraceutical and functional food industries to maximize the use of crayfish processing by-products.

Combined Role of Inflammatory Biomarkers and Red Blood Cell Distribution Width in Predicting In-hospital Outcomes of Acute Ischemic Stroke Patients Undergoing Thrombolysis.

BACKGROUND: To investigate the combined effect of red blood cell distribution width (RDW) and inflammatory biomarkers on in-hospital outcomes of acute ischemic stroke(AIS) patients with thrombolysis. METHODS: 417 AIS patients with thrombolysis were included. The participants were divided into four groups according to the cut-off of white blood cell (WBC) or C reactive protein (CRP) and RDW: LWLR, LWHR, HWLR, and HWHR; or LCLR, LCHR, HCLR, and HCHR (L-low, Hhigh, W-WBC, C-CRP, R-RDW). Logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of in-hospital pneumonia and functional outcome across the four subgroups. RESULTS: Patients with higher RDW and inflammatory biomarkers levels have the highest risk of in-hospital outcomes. Compared with patients in the LWLR group, the ORs (95% CIs) of those in the HWHR group were 12.16 (4.21-35.14) and 9.31 (3.19-27.17) for in-hospital pneumonia and functional outcome. The ORs (95% CIs) of those in the HCHR group were 6.93 (2.70-17.78) and 3.38 (1.10-10.39) for in-hospital pneumonia and functional outcome, compared with patients in the LCLR group. Simultaneously adding RDW and WBC or CRP to the basic model with established risk factors significantly improved risk discrimination and reclassification for pneumonia and functional outcome (all p <0.05). CONCLUSIONS: Combined RDW and inflammatory biomarkers within 4.5 hours had a better predictive power for in-hospital outcomes of AIS patients with thrombolysis.

A palladium-doped ceria@carbon core-sheath nanowire network: a promising catalyst support for alcohol electrooxidation reactions.

A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique interconnected one-dimensional core-sheath structure is revealed to facilitate immobilization of the metal catalysts, leading to the improved durability. This core-sheath nanowire network opens up a new strategy for catalyst performance optimization for next-generation fuel cells.

Polyelectrolyte assisted synthesis and enhanced oxygen reduction activity of Pt nanocrystals with controllable shape and size.

The shape control of platinum nanocrystals is significant to the enhancement of their catalytic performance in terms of activity and selectivity. However, it still remains a major challenge to prepare Pt nanocrystals with tunable shape and clean surface in an eco-friendly way. This article develops a facile and green strategy to prepare well tuned platinum nanocrystals employing poly(diallyldimethylammonium chloride) (PDDA) as the capping agent, reductant, and stabilizer simultaneously in a facile hydrothermal process. It is identified that the variation of PDDA concentration is crucial to control the growth of crystalline facets, leading to the formation of cubic, truncated cubic, and octahedral Pt nanocrystals with sizes tunable from ca. 17 nm to ca. 50 nm. The resultant Pt nanocrystals exhibit excellent electrocatalytic activity and stability toward the oxygen reduction reaction (ORR) in acidic media compared with those of commercial Pt black and the state-of-the-art Pt/C catalyst. It is proposed that the preferential Pt surface and the decoration of PDDA, which modulates the electronic structures and electrooxidation of Pt nanocrystals, synergistically contribute to the enhanced catalytic performance.